1. Field
The present invention relates to a differential current mirror circuit that copies a current by an arbitral magnitude.
2. Description of the Related Art
Conventionally, a current mirror circuit is a fundamental circuit block of analog circuits. As a current mirror circuit that processes a differential signal, an analog circuit cell is commonly known that includes the following components: (1) a current-sinking input terminal; (2) an input unit that is connected to the input terminal and utilizes low impedance that is of a bipolar transistor of first polarity and due to negative feedback; (3) a current-sourcing output terminal; (4) an output unit that is connected to the output terminal and utilizes high collector impedance of a bipolar transistor of second polarity; and (5) a processing unit that executes a given process according to the sinking current from the input unit, and sources the current through the output unit. By using a differential current, a signal is passed between current-sourcing output terminals and current-sinking input terminals of different analog circuit cells (see, for example, Japanese Patent No. 2610361).
However, the circuit cannot eliminate the in-phase current. As a result, the error of bias current due to the in-phase current caused by the fluctuation of power supply and/or the mismatch of transistors is amplified as it is, thereby impairing the accuracy of the signal processing.